The location data in these networks is very inaccurate. Your OS and browser actually do a pretty good job of locking down your location data unless you give explicit permission. It's in the ad network's interests to lie about the quality of their data - so a lot of the "location" data is going to be a vaguely accurate guess based on your IP address.
But also, location data is really important to ads right now because, contrary to common perception, per user tracking is very, very hard. Each SDK might be tattling on you, but unless you give them a key to match you across apps, each signal from each app is unique. Which is why you are often served advertisements based on what other people on your network is searching - it's much easier to just blast everyone at that IP address than it is to find that specific user or device again in the data stream.
Bidstream data in particular is very fraught. You're only getting the active data at the point the add is served, but it's not easy to aggregate in any way. You'll be counting the same person separately dozens or hundreds of times with different identifiers for each. The data you get from something like Mobilewalla is not useful for tracking individuals so much as it's useful for finding patterns.
I think it's pretty telling from the few examples shared about how agencies actually use the data:
>"CBP uses the information to “look for cellphone activity in unusual places,” including unpopulated portions of the US-Mexico border."
>According to the Wall Street Journal, the IRS tried to use Venntel’s data to track individual suspects, but gave up when it couldn’t locate its targets in the company’s dataset.
>In March 2021, SOCOM told Vice that the purpose of the contract was to “evaluate” the feasibility of using A6 services in an “overseas operating environment,” and that the government was no longer executing the contract
Something is going to have to be figured out about this data - realistically the only way is a sunset on customized advertisements. However, I would personally not be worried (yet) that the government is going to be able to identify an individual and track them down using these public sources as they currently are.
Let me share a thing:
Factual, a company that specializes in hyperlocal geofencing, uses geofencing much smaller than the self-regulation that their industry allows in their own rules. I learned this after a coworker quit because our company was allowing ad targeting to people using these smaller geofences. The whole company had an all-hands about it where the CEO of the company told everyone that we were not going to stop using Factual nor the smaller-than-allowed geofences because we, ourselves, were not the ones to produce those geofences. We were just a man in the middle helping to build a system to track people at high resolution.
Please try to reconcile with what your industry has and continues to destroy.
I don't see anything contradictory between your comment and the OP. Having an amoral CEO who condones breaking geotargeting self-regulation doesn't contradict OP's claim that it's hard to tie geotargeting data in bidstreams back to a particular person.
I won't claim with certainty that this is the case, but it seems likely that Factual was overselling their capabilities. That, or they relied specifically on having users grant high precision location data access and had nothing otherwise.
Apps that already need location data are probably the most likely sources of collecting such data - food apps, dating apps, chat apps you have sent your location in, ...
You'd be surprised what can be done when data from different source is fused together.
Large-Scale Online Deanonymization with LLMs: https://news.ycombinator.com/item?id=47139716
Robust De-anonymization of Large Sparse Datasets: https://www.cs.cornell.edu/~shmat/shmat_oak08netflix.pdf
Also, people who post under their real name are likely to write with their real voice:
> Any deanonymization setup with ground truth introduces distributional biases. In our cross-platform datasets, the pro-files are likely easier to deanonymize than an average profile: the very fact that ground truth exists implies that the user may not have cared about anonymity in the first place. Similarly, two split-profiles of a single user are inherently alike, whereas two pseudonymous accounts of the same person (e.g., an official and a pseudonymous alt account) might expose more heterogeneous micro-data.
The problem is that we have markets where we: - Incentivize organizations to pursue profits at the expense of everything else, which includes social good and civic rights - Rarely hold bad actors accountable (and almost never in a timely manner)
Which means, given enough time, we're always going to trend to whatever makes the most money. Targeted advertising makes money, and will continue to do so unless or until we collectively decide to make it a greater risk to profits than it is today.
Eg by running standard Android? That doesn't have eg secure app spawning, so apps can profile app initialisation data AIUI
And probably 10 other things behind the scenes that GrapheneÓS plugs?
Aren't there many examples of these? For example IMEI, IMSI, phone number, etc?
Even without "unique" signals, isn't it fairly trivial to identify a user with a handful of "not very unique" signals? User-agent, a few recent IP addresses, browser capabilities, list of installed apps, device operating system properties, etc?
There are services out their that help you with the data that is already out there on you.
All DeleteMe does is save you the time of manually making takedown requests, which is not that onerous in the first place. I've done plenty of my own. But that doesn't prevent online advertising databases from profiling me or you. And it's been happening for years - this isn't new at all.
https://www.wired.com/story/how-pentagon-learned-targeted-ad...
https://securitylab.amnesty.org/latest/2025/12/intellexa-lea...
The fact that we still just allow arbitrary 3rd party code to run through ad networks is bizarre.
It's interesting to imagine how things would change if those ad-networks were legally liable for their role in spreading scams and malware.
Whatever you are doing is meaningless privacy theatre
Of course, you can do more, such as running only trusted software (i.e., free software) on your devices, not using Internet-of-Shit devices anywhere in your home, and making sure your car is not snooping on you through it's own cellular modem.
This is another reason why you should not be carrying a phone everywhere except for times where you absolutely need one.
There’s really not any legal practical way to avoid ALPRs.
I’m pretty sure the government knows where I am 24/7. I’m not going to worry about targeted advertising by the government anymore and just worry about it the people reselling it to non-governments for use.
https://web.archive.org/web/20070920193501/http://www.radaro...
The invasion of privacy has been slow, creeping, and just waiting for that Turnkey Tyrant. We fooled ourselves into thinking we'd never elect someone who would turn that key. But in reality the key has been slowly turning, until finally it opened the latch
There is an ethical framework for handling personal data collected and maintained by the US govt called the Fair Information Practice Principles (https://www.fpc.gov/resources/fipps/).
It really is too bad that "any legal purpose" is the stated boundary for our elected govt rather than a more noble appeal to public service.
The US government contracts with commercial data providers stipulate that all US data must be removed. There are quite a few regulatory controls that are adhered to.
> 1. Disable your mobile advertising ID
> 2. Review apps you’ve granted location permissions to.
I'm surprised they missed the most important step, which is blocking the advertisers from collecting your data in the first place. This is easily done in the browser with uBlock Origin and system-wide with DNS filtering.
A law that says the government can't ask for this stuff doesn't help very much. They'll ignore it when it suits them.
A law that says it's illegal for private companies to hand it over would be better. When caught between a request from the government and a law that says they're not allowed to honor that request, there's a good chance they'll obey the law rather than the rogue agency.
A law that says it's illegal for private companies to collect this data in the first place would be even better. It could still be worked around, but it's more likely to be uncovered, and they'd only get data after the point where they convinced a company to start collecting it.
- you always denied those popups
- .. including any hidden legitimate interest sections that are being treated as a second, opt-out "consent" for things that really don't actually qualify as legitimate interest
- and the companies actually followed it
Then in theory the companies won't have that data. But doing 1 is tedious, companies exercise dark patterns to avoid you doing 2, and it's hard to audit if they've done 3, so most people are probably in those data sets.
Also, a government likely to buy this data for purposes like in the original article, is unlikely to be the type of government that goes around slapping companies for not complying with privacy regulation on that data.
The issue here isn’t simply “lack of privacy law.” It’s:
1. apps collecting precise location data in the first place,
2. adtech infrastructure broadcasting that data through RTB,
3. brokers aggregating and reselling it,
4. government agencies buying it to avoid the constraints that would apply if they tried to collect it directly, and
5. regulators failing to stop any of the above in a meaningful way.
European law is relevant to some of that, but not as a magic shield. GDPR and ePrivacy principles are obviously more restrictive on paper than the US free-for-all, especially around consent, purpose limitation, data minimization, and downstream reuse. But “on paper” is doing a lot of work there. Europe has had years of complaints about RTB specifically, and yet the adtech ecosystem did not exactly disappear. That should tell you something.
So the real answer is: yes, a stronger privacy regime can help, but no, this is not a problem that gets solved by vaguely importing “European-style privacy laws” as a concept. If the underlying business model still allows mass collection, opaque sharing, and resale of location data, then state access is a policy choice away. Governments don’t need to build a panopticon if the commercial sector already did it for them.
Also, the most important legal question here is not just whether private companies should be allowed to collect/sell this data. It’s whether the government should be allowed to buy commercially available data to do an end-run around constitutional and statutory limits. That is a distinct issue. You need rules for both the commercial market and state procurement, otherwise the state just shops where the Fourth Amendment doesn’t reach.
In other words, the contrast is not “Europe = protected, US = authoritarian.” The contrast is between systems that at least attempt to constrain collection and reuse, and systems that let surveillance markets mature first and ask questions later. Even in Europe, enforcement gaps, law-enforcement carveouts, and institutional incentives matter enormously.
So if the goal is to understand the story, the useful question isn’t “would Europe stop this?” It’s “what combination of collection limits, resale bans, procurement bans, audit requirements, and enforcement would actually make this impossible in practice?” Anything short of that is mostly aesthetics.
Unless you have some body which is a) serious about enforcement, b) sufficiently toothful to make a dent and c) not undermined by wider geopolitical posturing or economic neutering, you can have all of the regulation you might want and still end up in the same place. I'm not arguing that we shouldn't try and control this, but that we have some extremely large genies to stuff back into bottles along the way.
More of us should learn to do things the hard way more often, and to be familiar with less-convenient things. There are life-changing advantages to doing things the hard way at least some of the time.
It was able to track me as long as my IP address didn't change, but as soon as I switched VPN endpoints, it gave me a new identifier.
> https://coveryourtracks.eff.org/
You quickly discover how difficult it really is to avoid a unique fingerprint.
Lots of folks in this thread are focusing on DNS and VPN to avoid detection, which of course can help, but a huge number of identifiable bits come from your browser's APIs:
User Agent
Screen Size and Color Depth
System Fonts
Hash of canvas fingerprint
Hash of WebGL fingerprint
WebGL Vendor & Renderer
Touch Support
AudioContext fingerprint
Hardware Concurrency
Device Memory
Platform
Language
Timezone
Timezone offset
Browser Plugin Details
etc etc
It's similar to when you use Linux or an obscure privacy-preserving browser. You've made yourself way more unique just by doing that.
(I'm not sure how the math works out though, vs. actually running all that nasty tracking stuff.)
I don’t know, but it seems like it’s overselling its capabilities. I tried with Firefox Focus and it said I’m using incognito (private mode) and assigned a unique visitor ID. Immediately tried with a private tab in Safari on iOS and it said I’m not using incognito (private mode) and assigned a new unique visitor ID. Then I switched networks and tried. One more unique visitor ID.
I’m not claiming that fingerprinting is not possible, but this website is not good at it. Seems like it uses plain cookies.
I just opened it in another browser and got another ID. Did I win?
For some reason using Microsoft Edge is deemed suspicious.
I beat it, I think... nothing much there. I use a VPN and NextDNS.io.
Most slop mobile applications, that many people have on their phones are basically spyware pretending to be games/whatever.
Programatic advertising technology was created for intelligence purposes, these companies and their methods are very sophisticated.
Does sharing location with family (Android) leak any data?
The real problem is that tech giants only need to claim that their use of data is appropriate, and they can then feel free to use it to provide "better" services.
After all, they should never have been allowed to do this from the very beginning. Users aren't fools—they can learn too. So what we need isn't automatic push, but easier ways to actively seek things out.
The only people who didn't understand this were either delusional or being paid not to.
For years, people have been sharing everything they do, what they do, people they spent time with, where they live.
Advertisement industry just adds more info to complete your profile, what you buy, what you watch, what you speak online, etc.
I think it’s more concerning that programmers seem to have no care or shame about designing systems that works against the users’ interests. Did you share something intimate in our chat? Well it’s not E2E, moron, we have that now. How could you be this stupid?
I can’t think of another profession (except pure value extraction types) which revels in exploiting people for not having the time or care to arrange their digital lives around the booby traps that nerds set for them.
Anecdotally, it feels like it fits right in with the "if there's no cop around to give me a ticket, I can drive however I want" attitude I've seen post-Covid. People entering two-way turn lanes or HOV merge lanes to PASS people in the main lane. People going through stop signs without any stopping while I'm waiting for my turn. Using the HOV on-ramp lane with only the driver to merge onto the freeway where it's clearly marked "24 hour HOV lane", etc.
It's as if the entire social compact evaporated during/after Covid, and "everyone only out for themselves" is the norm now.
Or maybe I'm just more aware of it and more cynical.
When a poor lad comes on a work visa and is elevated from a literal poverty to a somewhat decent standard of living, would you expect them to stand up and make sure some camera recordings can’t be used in a way they aren’t supposed to be used? Do you expect them to even consider if their management may abuse that some years in the future (when the code is an unholy mess of duct tape and all the effort goes into making it work for the stated purpose), when their mind is all busy thinking about bills, health, family abroad, and the general sense of doom impending with pandemics and wars and extreme corruption all around? Nah, that lad’s also being exploited here, not exploiting others. Not that any sins are absolved but he’s a lot less of a monster than your comment paints. And there are corporations with tens of thousands of such lads and lasses and other folks. And that’s just one of myriad of possible nuances that break the trope of evil programmers screwing the world up.
Blame the rot that starts at the head, it’d be at least a bit more accurate.
> I can’t think of another profession
That’s because you framed the criteria so narrowly that it includes almost only programmers. And even then you still confused between management and implementors. And even then you’re forgetting the management, who’s definitely more to blame than workers.
It's not uncommon, but always disappointing to me, to see how out of touch most HN folks are when it comes to privacy and data. Usually privacy is dismissed as hyperbole, or tinfoil hat stuff, or only for people selling drugs on the darknet. It's not anymore. The minimum barrier to entry for simply not having your every thought and whim and search catalogued is high: Masking your IP address, masking your browser fingerprint, and simply not participating in a lot of parts of the internet.
These are your thoughts, your personal life, being dissected and catalogued and sold in an attempt to, at BEST, shape your behavior. At worst, see exactly when you cross the line into becoming "an agitator." It's the step you need before getting to "thoughtcrime." Why is this acceptable to anyone??? In exchange for free email?
We're all in the pot and the water is already starting to bubble. And I'm sure that the only replies I might get will be "Oh, but no, it's not anything like that." Sure.
This is simply the first time you're seeing it on US soil. https://www.wired.com/story/how-pentagon-learned-targeted-ad...
Yet two years ago, look how many people were incredulous, doubtful, or simply didn't care. https://news.ycombinator.com/item?id=39540738
Maybe now is a good time to bring up KOSA? Or maybe we should discuss that two years from now when it's too late to change anything.
https://www.eff.org/document/kids-online-safety-act-kosa https://www.eff.org/deeplinks/2025/05/kids-online-safety-act...
Like yeah, sure, governments collecting data deserves scrutiny. 100%. But at least in most democracies there are audits, oversight bodies, privacy commissioners, courts, access to information laws, etc. There are actual mechanisms where someone can ask “why are you doing this?” and force an answer.
Meanwhile we hand over our location, browsing habits, shopping patterns, sleep schedule, and probably our favorite pizza topping to dozens of private companies every day. Those companies can aggregate it, sell it, profile you, feed it into ad markets, train models with it, or ship it across borders… and most of the time nobody outside the company even knows it’s happening.
So yeah, data collection in general is worth debating. But the irony is wild when people lose their minds over the one place that at least has some governance and accountability, while the entire private ad-tech ecosystem is basically “trust us bro” with a 40-page terms of service nobody reads.
"Jeffrey Epstein’s Island Visitors Exposed by Data Broker" - https://www.wired.com/story/jeffrey-epstein-island-visitors-...
A very easy, effective, multi-layer setup:
1. Browser adblocker
2. Pi hole running locally
3. Pi hole at your home network router level
And 4, not as easy but effective, a firewall like Little Snitch
Edit: the other good news is your old data loses value quickly, so starting today is still very effective: you haven’t missed the boat yet!
1. Adblocking via private DNS (e.g. https://mullvad.net/en/help/dns-over-https-and-dns-over-tls)
2. Prefer websites over native apps wherever possible
3. Browser adblocker
Hosts file adblocking is also possible on a phone where you have root.
